An epidemic of infectious diseases capable of spreading across a large region, e.g., a continent or the entire world, can be hugely costly to societies. Such incidences include pandemics of influenza, smallpox, tuberculosis, human immune deficiency virus (HIV), and Severe Acute Respiratory Syndrome (SARS). The World Bank estimated in 2008 that a flu pandemic could cost $3 trillion and result in a nearly 5% drop in world gross domestic product (GDP). The World Bank further estimated that more than 70 million people could die worldwide in a severe pandemic. Others have estimated that a flu pandemic could cause an economic recession in the United States, costing the country at least $500 billion to $675 billion in the near term. In 2003, SARS disrupted travel, trade and the workplace in the Asia Pacific region and cost the region about $40 billion. The SARS pandemic lasted for six months, killing at least 1000 of the 8,000 people it infected in 25 countries. The city of Toronto, CA was closed to air traffic for several weeks and suffered significant financial loss.
In 2009, the spring flu season cost billions of dollars even though it only lasted only a few weeks. The 2009-2010 winter flu season is anticipated to start by late August and could run through April 2010. Even if working vaccines are available, their supplies are expected to be limited and cannot be expected to stop the flu for several months. Economic losses can be minimized if the flu can be contained through proactive screening that allows for effective anti-viral administration and narrowly targeted quarantines.
Economic loss due to “avoidance behaviors” is even greater than the cost of treating flu victims. The cost includes reducing air travel, avoiding travel to infected destinations and reducing consumption of services, such as mass transit, dining out, shopping, etc. According to the World Bank, if a flu epidemic approached the 2.5% mortality rates similar to 1918-19 flu, avoidance behaviors would cost a region five times more than losses from mortality or work absenteeism.